At present, a plurality of methods are available for generating a sine wave by using a digital circuit. For example, the sine wave is generated by using Matrix Laboratory (MATLAB) or other software tools. However, the current problem is that data information of the sine wave is all stored in a value search table, and when generating the sine wave, the MATLAB or the other software tools directly output the data in the value search table according to the actual needs, but are not capable of generating data information of the sine wave except the value search table. Therefore, the conventional methods are somewhat limitative. Some methods may only be used for generating sine waves with specific frequencies, or some methods require a great circuit area during generation of sine waves with different frequencies. In addition, inaccurate frequency or drift of the sine wave may be present. Therefore, high power consumption and high cost are caused in the generation of the sine wave by using the digital circuit, and the time-domain and frequency-domain effects of the generated sine wave are poor.